Many combustion engines for small powered equipment include an engine flywheel to moderate speed fluctuations in the engine. Specifically, the flywheel can be designed to be able to develop an inertia large enough such that quick spurts by the engine or sudden loads (e.g., a lawnmower hitting a clump of weeds) are evened out. Because of this large inertia, however, it can be difficult to quickly slow and/or stop the operation of the engine because of the time needed to dissipate the energy stored in the flywheel. To speed this slowdown, in particular to meet regulations regarding maximum stopping times (e.g., blade stop time for a lawnmower), a brake can be configured to act directly on the engine flywheel to actively dissipate the stored energy. In such systems, the energy of the spinning flywheel is generally lost (e.g., dissipated as heat) upon braking.
In some contrasting configurations, such as portable generators and alternators for some small motor vehicle engines (e.g., motorcycles, scooters), similarly-structured combustion engines can provide high power generation from the rotation of a rotor/flywheel by converting the mechanical energy of the flywheel into electrical energy. Further, because these engine-generators generally don't have any need to stop quickly, these systems generally don't rely on a brake mechanism to slow the operation of the engine, and thus much of the energy stored in the flywheel can be effectively recaptured as electrical power over time.
Although the powered equipment and dedicated engine-generators are designed to serve much different purposes, it would be desirable for advantageous aspects of both types of systems to be integrated together. For example, in a lawnmower, instead of dissipating all of the energy stored in the flywheel during braking, it would be advantageous to recapture at least some of that stored energy and convert it to electricity in a manner similar to an engine-generator. It is undesirable, however, to apply a brake to the component to which magnets are mounted for power generation because the braking can cause heat to build up, the component to deflect, and any adhesives to be stressed. These factors can diminish the ability of the electrical generation components of the system to operate as intended, and such factors can further cause the electrical generation system to fail prematurely.
As a result, it would be desirable for an engine flywheel to be able to integrate electric power generation with rapid engine braking without each of the two operations impeding the operation of the other.